Project Summary - Core C (Protein Chemistry Core) The Protein Chemistry Core will continue to provide the research groups in the Program Project with the technical expertise and equipment required for the isolation and sequence analysis of receptor fragments containing the sites of photoincorporation by general anesthetics. In addition, the Core provides computational resources for the homology modeling and docking studies that are necessary to interpret the protein chemistry results in terms of models of receptor structure (Projects 1 and 2) and to provide guidance in the design and interpretation of mutational analyses (Project 3) that further assess the structure and function of the identified binding sites. The Core is under the supervision of Dr. Cohen and is located in his laboratory. Major equipment currently available in the Core include (i) an Applied Biosystems 492 Procise automated Protein Sequenator and in-line amino acid analyzer; and (ii) 2 Agilent 1100 HPLCs equipped with UV and fluorescence detectors; and (iii) an Agilent 1100 capillary LC system. The biochemical characterization of anesthetic binding sites in ligand-gated ion channels requires the use of highly specialized techniques not normally available in protein chemistry core facilities which usually do not accept radioactive samples either for Edman degradation or mass spectrometry. The identification of drug binding sites within the hydrophobic domains of integral membrane proteins poses unique problems for peptide isolation and characterization by either Edman degradation or mass spectrometry. It is the function of the Core to provide the appropriate equipment and highly skilled protein chemists who can interact directly with the research projects to develop and carry out the appropriate research strategies and to educate the investigators about the necessary protein chemistry techniques to be carried out either in the Core or in the investigator's lab. In the previous funding period, novel experimental strategies were developed to characterize anesthetic photolabeling of amino acids in each of the transmembrane helices of the a13g2 GABAAR, which led to the identification of a second class of GABAAR anesthetic binding sites, and in serotonin 5-HT3 receptors. This Core will now provide similar expertise for the characterization of novel anesthetic binding sites in a13g2 and a43d GABAARs and GlyRs.